The invention relates to a device for the automatic formation and sewing of a hem at an endless edge of an opening of variable width in a workpiece, having hem-forming means on a sewing machine controlled by a logic device.
In the patent specification DE 27 45 868 C3, a plurality of rollers and two freely rotatable cloth carrier cages are provided for receiving the workpiece, the edges of which rollers and cages are disposed at a distance in front of the edge of a cloth carrier plate. Two rollers, which are movable upwardly and downwardly, serve as cloth tensioners, and switches for sensing the size of the workpiece are associated with the rollers. The large number of parts required results in a complicated, and hence, expensive construction. The minimum width of the openings in the workpieces is disadvantageously limited owing to the fact that it is necessary for the workpiece to embrace the cloth carrier cages and the tensioning rollers.